That which is unformed or undeveloped; the principle which lies at the bottom of any development; an unfinished beginning.
- A fundamental element, principle, or skill, as of a field of learning. Often used in the plural.
- Something in an incipient or undeveloped form. Often used in the plural: the rudiments of social behavior in children; the rudiments of a plan of action.
- Biology An imperfectly or incompletely developed organ or part.